CN110157312B - A kind of self-healing coating with photothermal effect and preparation and application method thereof - Google Patents

Abstract

The invention discloses a self-repairing coating with a photo-thermal effect and a preparation method and an application method thereof, and is characterized in that the coating consists of titanium nitride nano-particles with the mass fraction of 0.3-5.0% and the balance of resin. The coating is prepared by the following method: firstly, titanium nitride nano particles are uniformly dispersed in resin, then the titanium nitride nano particles are spin-coated, spray-coated or blade-coated on the surface of a substrate, and a self-repairing coating with a photo-thermal effect is obtained after curing. The titanium nitride-resin composite coating prepared by the method has good corrosion resistance; when the surface of the coating is damaged, the nano titanium nitride excites plasmon resonance under illumination, and light energy can be directly converted into heat energy, so that the organic matter is promoted to melt and heal the damaged interface, and the protective effect of the coating on the substrate is recovered. The preparation method has the advantages of simple preparation process, low production cost, good corrosion resistance and self-repairing performance of the coating, repeated self-repairing, and wide application prospect.

Description

A kind of self-healing coating with photothermal effect and preparation and application method thereof

technical field

The invention relates to a self-healing coating with photothermal effect and a preparation and application method thereof, belonging to the field of corrosion-resistant coating materials.

Background technique

As a physical shield, coating protection can effectively inhibit the occurrence of corrosion on the surface of metal substrates, and it is one of the most effective means of metal corrosion prevention. However, the coating will inevitably be damaged and cracked during service, resulting in a significant drop in anti-corrosion performance. Therefore, there is an urgent need to develop smart coatings with self-healing functions. The self-healing coating can promote the melting of the coating in the damaged area and heal the damaged interface through external stimuli such as light, electricity, heat, and magnetism. This method can repair large-scale surface damage and is conducive to restoring the physical and chemical properties of the coating itself. properties and shielding. In recent years, new self-healing coatings that generate heat through light have received extensive attention from scholars. Photothermal-triggered self-healing has the following significant advantages: (1) there is no strict requirement for the type of coating material, and both covalent and non-covalent bonds can be repaired; (2) the self-healing process can be remotely triggered by a light source, It is of great significance for material repair in special environments such as underwater and vacuum conditions; (3) By adjusting the illumination position and spot size, local high-precision self-repair of the coating can be achieved to avoid thermal damage to the intact area of the coating. and side effects, which are difficult to achieve by traditional heating repair methods; (4) By adjusting conditions such as the wavelength and intensity of the light source, the photothermal effect can be optimized. Therefore, the photothermal method has great research value and economic benefits in coating research and development. Existing reports have achieved photothermal self-healing by adding graphene, carbon nanotubes, gold nanoparticles, etc. to the coating, but the addition of these substances will significantly increase the preparation cost of the coating, so it is urgent to develop new low-cost , high-performance photothermal materials, and apply them to the field of photothermal self-healing coatings. Nano-titanium nitride has light heat generation performance based on plasmon resonance, and it has good light absorption rate in the entire visible light and near-infrared wavelength range, which is conducive to the efficient use of light energy; nano-titanium nitride also has low price. , high melting point, chemical stability and good corrosion resistance. Therefore, the development of photothermal self-healing coatings based on nano-titanium nitride has broad application prospects; at the same time, the appropriate particle size and shape of titanium nitride should be selected to ensure good dispersion and binding force in the coating.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a self-healing coating with photothermal effect and its preparation and application method.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A self-healing coating with photothermal effect is characterized in that the coating is a composite structure composed of titanium nitride nanoparticles and resin.

The diameter of the titanium nitride nanoparticles is 10nm to 80nm, and the mass fraction is 0.3% to 5.0%; the resin is polyurethane PU, polyacrylic acid PAA, polystyrene PS, polyvinyl alcohol PVA, and modified epoxy. Any one; the thickness of the titanium nitride-resin composite coating is 50 μm to 200 μm.

A method for preparing the above-mentioned self-healing coating with photothermal effect, characterized in that: firstly, titanium nitride nanoparticles are uniformly dispersed in tetrahydrofuran or N,N-dimethylformamide, and then uniformly mixed with a resin solution to form a uniform Then, the titanium nitride-resin composite solution is uniformly coated on the surface of the substrate by spin coating, spray coating or blade coating, and cured at a temperature of 40 ° C ~ 100 ° C for 12 h ~ 24 h, and finally a light Self-healing coatings for thermal effects.

The self-healing method of the coating as described above is characterized in that: using a near-infrared laser of 5W/cm ² to 50W/cm ² to irradiate the damaged area of the coating, the inner coating gradually melts and heals the damaged interface within 10s to 60s, and stops The coating re-curs after exposure to light, thereby restoring the protection of the substrate.

The present invention has the following advantages and outstanding technical effects: the present invention prepares a self-healing coating with photothermal effect. The titanium nitride-resin composite coating has good corrosion resistance; when the surface of the coating is damaged, the nano-titanium nitride excites plasmon resonance under light to directly convert the light energy into heat energy, thereby promoting the melting and healing of organic matter Damage the interface and restore the protective ability of the coating to the substrate. The preparation process of the invention is simple, the production cost is low, the coating has good corrosion resistance and self-repairing performance, and can repeat self-repairing for many times, and has broad application prospects.

Description of drawings

Fig. 1 is the heating curve of the surface temperature of the titanium nitride-polyacrylic acid composite coating and the pure polyacrylic acid coating prepared in Example 1 with the illumination time.

Fig. 2a is a scribed photo of the surface of the titanium nitride-polystyrene composite coating prepared in Example 2; Fig. 2b is a photo of the surface scribed of the titanium nitride-polystyrene coating prepared in Example 2 in the light from Repaired photo.

3 is the electrochemical impedance spectrum of the titanium nitride-polyurethane composite coating prepared in Example 3 when the coating is not damaged, after the coating is damaged, and after the coating is self-repaired.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

The invention prepares a self-healing coating with photothermal effect. In the present invention, titanium nitride nanoparticles are uniformly dispersed in tetrahydrofuran or N,N-dimethylformamide, and then uniformly mixed with a resin solution to form a homogeneous liquid; and then the titanium nitride-resin composite solution is spin-coated and sprayed It is evenly coated on the surface of the substrate and cured by means of blade coating to obtain a self-healing coating with photothermal effect. The titanium nitride-resin composite coating has good corrosion resistance; when the surface of the coating is damaged, the nano-titanium nitride excites plasmon resonance under light to directly convert the light energy into heat energy, thereby promoting the melting and healing of organic matter Damage the interface and restore the protective ability of the coating to the substrate. The preparation process of the invention is simple, the production cost is low, the coating has good corrosion resistance and self-repairing performance, can self-repair many times, and has broad application prospects.

The present invention will be specifically described below with reference to the accompanying drawings 1 to 3 and the embodiments. The following examples are illustrative, not restrictive, and the protection scope of the present invention cannot be limited by the following examples.

Example 1

1. Sand the stainless steel sheet with sandpaper, then ultrasonically clean it with acetone, alcohol, and deionized water in sequence and dry it;

2. Disperse titanium nitride nanoparticles with a particle size of 20nm in tetrahydrofuran: get 0.006g of nano-titanium nitride and add it to 2g of tetrahydrofuran, and magnetically stir for 30min at a rotating speed of 600rpm;

3. Dissolve 2g of polyacrylic acid in 6g of tetrahydrofuran, and dissolve into a homogeneous solution at 80°C and a rotating speed of 400rpm;

4. Mix the titanium nitride with the polyacrylic acid solution, and uniformly disperse it for 20 minutes at 90°C and 800 rpm to ensure that the mass fraction of the titanium nitride solvent after volatilization is 0.3%;

5. The titanium nitride-polyacrylic acid composite solution is evenly coated on the surface of the stainless steel sheet by a bar coating method;

6. Dry in an oven at 80°C for 12h, and the coating thickness after curing is 50μm.

7. As a control, a pure polyacrylic acid coating was prepared on a stainless steel sheet using the same bar coating process and curing method.

8. Use 5W/cm ² 785nm near-infrared laser to irradiate the surfaces of the titanium nitride-polyacrylic acid composite coating and the pure polyacrylic acid coating, and measure the temperature at the edge of the laser spot with a thermocouple.

Fig. 1 is the heating curve of the surface temperature of the titanium nitride-polyacrylic acid composite coating and the pure polyacrylic acid coating prepared in Example 1 with the illumination time. Due to the plasmonic properties of nano-titanium nitride, plasmon resonance is generated under illumination, which can directly convert light energy into heat energy. Therefore, the surface temperature of the titanium nitride-polyacrylic acid composite coating gradually increases with the illumination time. , rose to 70°C in 3 minutes, and then saturated. The pure polyacrylic acid coating does not have the ability to absorb heat, so the heat absorption of the coating is not obvious after laser irradiation.

Example 2

1. Sand the aluminum alloy sheet with sandpaper, then ultrasonically clean it with acetone, alcohol, and deionized water in sequence and dry it;

2. Disperse titanium nitride nanoparticles with a particle size of 30nm in tetrahydrofuran: get 0.06g of nano-titanium nitride and add it to 2g of tetrahydrofuran, and magnetically stir for 30min at a rotating speed of 600rpm;

3.3g of polystyrene powder was dissolved in 50mL of tetrahydrofuran for use;

4. Mix the titanium nitride with the polystyrene solution, and stir at 70 rpm to reach a certain viscosity to ensure that the mass fraction of the titanium nitride solvent after volatilization is 2.0%;

5. Spray the titanium nitride-polystyrene composite solution on the surface of the aluminum alloy sheet, and uniformly spray the composite solution on the aluminum alloy sheet with a spray gun at 0.6 MPa, and the nozzle reaches 10 to 15 cm on the surface of the sample;

6. Dry in an oven at 60°C for 12h, and the coating thickness after curing is 90μm.

7. Use a scalpel to make a scratch with a width of about 60 μm on the surface of the coating, and then irradiate the surface of the damaged composite coating with a 20W/cm ² 808 nm near-infrared laser.

Fig. 2a is a scribed photo of the surface of the titanium nitride-polystyrene composite coating prepared in Example 2; Fig. 2b is a photo of the surface scribed of the titanium nitride-polystyrene coating prepared in Example 2 in the light from Repaired photo. When the coating is damaged, titanium nitride excites plasmon resonance under light to directly convert light energy into heat energy, thereby promoting the melting of organic matter, and the damaged interface can be healed within 10 s.

Example 3

1. Grind the carbon steel sheet with sandpaper, then ultrasonically clean it with acetone, alcohol, and deionized water in sequence and dry it;

2. Disperse titanium nitride nanoparticles with a particle size of 80nm in N,N-dimethylformamide: take 0.08g of nano-titanium nitride and add it to 1g of N,N-dimethylformamide, at a speed of 600rpm under magnetic stirring for 30 min;

3. Dissolve 2g of polyurethane in 7g of N,N-dimethylformamide, and dissolve it into a homogeneous solution at 90°C and a rotating speed of 800rpm;

4. Mix the titanium nitride with the polyurethane solution, and uniformly disperse it for 20 minutes at 90° C. and 800 rpm, to ensure that the mass fraction of the titanium nitride solvent after volatilization is 4.0%;

5. Spin-coat the titanium nitride-polyurethane composite solution on the surface of the carbon steel sheet, the speed is 300rpm, and the time is 20s;

6. Cured in an oven at 55°C for 24h, the coating thickness after curing is 100μm.

7. Use a scalpel to make a scratch with a width of about 60 μm on the surface of the coating, and then irradiate the surface of the damaged composite coating with a 808 nm near-infrared laser of 30 W/cm ² .

8. Measure the electrochemical impedance spectrum of the intact coating, the damaged coating and the self-healed coating using an electrochemical workstation, and the test solution is 3.5 wt.% NaCl.

3 is the electrochemical impedance spectrum of the titanium nitride-polyurethane composite coating prepared in Example 3 when the coating is not damaged, after the coating is damaged, and after the coating is self-repaired. The low-frequency impedance modulus value of the complete coating reaches 2.9×10 ⁹ Ω·cm ² , indicating that the coating has good anti-corrosion performance; however, when the coating surface is scratched, the low-frequency impedance modulus value of the coating decreases to 7.3×10 ⁴ Ω cm ² , indicating that the electrolyte ions have eroded the exposed metal surface; when the coating undergoes photothermal self-healing, the low-frequency impedance modulus value returns to 2.5×10 ⁹ Ω·cm ² , and the coating has recovered its protective performance to the substrate. .

Claims (2)

1. An application method of a self-repairing coating with a photo-thermal effect is characterized in that the coating is a composite structure consisting of titanium nitride nano-particles and resin; the diameter of the titanium nitride nano-particles is 10 nm-80 nm, and the mass fraction is 0.3% -5.0%; the resin is any one of Polyurethane (PU), polyacrylic acid (PAA), Polystyrene (PS), polyvinyl alcohol (PVA) and modified epoxy; the thickness of the titanium nitride-resin composite coating is 50-200 mu m;

using 5W/cm²~50W/cm²The near-infrared laser irradiates the damaged area of the coating, the coating is gradually melted in 10 s-60 s and heals the damaged interface, and the coating is re-solidified after the irradiation is stopped, so that the protective effect on the substrate is recovered.

2. A method of preparing a self-healing coating having a photothermal effect as claimed in claim 1, comprising the steps of:

(1) uniformly dispersing titanium nitride nanoparticles in tetrahydrofuran or N, N-dimethylformamide, and uniformly mixing with a resin solution to form a homogeneous liquid;

(2) uniformly coating the titanium nitride-resin composite solution on the surface of the base material in a spin coating, spray coating or blade coating mode, and curing at the temperature of 40-100 ℃ for 12-24 h to obtain the self-repairing coating with the photo-thermal effect.

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